Validation of a New Portable Exhaled Nitric Oxide Analyzer, NIOX VERO®: Randomized Studies in Asthma

Introduction: Fractional exhaled nitric oxide (FeNO) is a non-invasive marker of airway inflammation, and a new portable analyzer (NIOX VERO ) is now available. Our studies aimed to assess the agreement of measurements between NIOX VERO and a reference device (NIOX MINO ) and assess the reproducibility of NIOX VERO . Methods: Paired FeNO readings were obtained from 112 subjects from both devices to assess agreement and reproducibility. FeNO readings were obtained from 122 subjects using NIOX VERO to assess inter-operator repeatability. All subjects had a diagnosis of asthma and were aged C7 years. Results: Agreement was shown with 90.8% of subjects within tolerance limits for the first valid FeNO measurement. Mean observed paired difference for the first valid FeNO measurement on each device was -4.6 ppb [95% confidence interval (CI) -5.825 to -3.377; p\0.0001]. Weighted Deming Regression Analysis showed a slope of 0.842 (95% CI 0.757, 0.927) and a y-intercept of -0.472 (95% CI -1.999, 1.055). Paired differences were centered close to 0. Intra-subject repeatability of NIOX VERO was significantly better than NIOX MINO (p = 0.0112). Further, inter-operator repeatability was achieved with NIOX VERO with a mean intra-subject variance of 6.61 ± 17.954 ppb (upper 95% CI 9.41) and an estimated standard deviation of 2.57 (upper 95% CI 3.07). The coefficient of variance was 0.066 ± 0.054 (upper 95% CI 0.074). Conclusion: Our findings show that the portable instrument NIOX VERO is clinically equivalent to NIOX MINO when used in an asthma population. The NIOX VERO analyzer gives reproducible, consistentmeasurements that are well within the technical specifications of the device, showing no observable pattern of a training effect oroperator-order effect on FeNOresults. Thus, our findings validate the NIOX VERO . Funding: Aerocrine AB, Solna, Sweden. Enhanced content To view enhanced content for this article go to http://www.medengine.com/Redeem/ BC87F0600B0A5026. Electronic supplementary material The online version of this article (doi:10.1007/s41030-017-0032-8) contains supplementary material, which is available to authorized users. K. Alving Department of Women’s and Children’s Health, Uppsala University, Uppsala, Sweden R. Anolik Allergy and Asthma Specialists, PC, Blue Bell, PA, USA G. Crater K. Rickard (&) Circassia Pharmaceuticals Inc., Morrisville, NC, USA e-mail: [email protected] C. F. LaForce North Carolina Clinical Research, Raleigh, NC, USA Pulm Ther DOI 10.1007/s41030-017-0032-8